Translation initiation factor a/eIF2(-gamma) counteracts 5' to 3' mRNA decay in the archaeon Sulfolobus solfataricus.

Hasenöhrl, David; Lombo, Tania; Kaberdin, Vladimir; Londei, Paola; Bläsi, Udo · Proc Natl Acad Sci U S A · 2008

basic_science · Level V

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Abstract

The trimeric translation initiation factor a/eIF2 of the crenarchaeon Sulfolobus solfataricus is pivotal for binding of initiator tRNA to the ribosome. Here, we present in vitro and in vivo evidence that the a/eIF2 gamma-subunit exhibits an additional function with resemblance to the eukaryotic cap-complex. It binds to the 5'-triphosphate end of mRNA and protects the 5' part from degradation. This unprecedented capacity of the archaeal initiation factor further indicates that 5' --> 3' directional mRNA decay is a pathway common to all domains of life.

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